Culture Media Types Composition Growth Conditions

Step 1: Understanding Mac-Conkey medium.
Mac-Conkey medium is both selective and differential. It is selective for Gram-negative bacteria and differentiates bacteria based on their ability to ferment lactose, turning the medium from yellow to red.
Step 2: Analyzing the options.
(1) Transport medium: Incorrect, Mac-Conkey medium is not used for transporting samples.
(2) Enrichment medium: Incorrect, Mac-Conkey medium is not an enrichment medium.
(3) Differential medium: Correct — Mac-Conkey medium is a differential medium, differentiating bacteria based on lactose fermentation.
(4) Selective Medium: Incorrect, although it has selective properties, it is not primarily classified as a selective medium.
Step 3: Conclusion.
Mac-Conkey medium is best described as a (3) Differential medium.